Tuesday, September 11, 2012

Uranus: King of the Ice Planets

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King of the Ice Planets
Uranus is one of the ice-planets, along with Neptune and Pluto and probably more are nearby that we haven't seen or discovered new things about. These planets primarily consist of methane, ammonia and water. Uranus' water is thought to be broken down into its hydrogen and oxygen parts with the methane and ammonia, creating a toxic ocean of mostly frozen chemicals. And although it's called an "icy" planet, its core is thought to be between 8,540.33°F - 12,140.33°F (5,000-7,000 kelvins). It's so cold because it has a low thermal flux (inner heat does not radiate out of the center), making the surface extremely cold, reaching lows of -224°F and the intensity of sunlight felt on the surface is only 1/400th that of Earth (no wonder it's so cold). What's even more awkward about this planet is in the picture to the left, depicting the polar ice caps on the planet's sides and the planet itself also spins north to south, rather than east to west as on Earth.
Another confusing quirk is the magnetic field, which does not originate from the planet's geometric center due to the planet's tilted axis (at 59°)...and although I don't like quoting Wikipedia, they explained it well, stating that "The magnetic dipole is shifted from the center of the planet towards the south rotational pole by as much as one third of the planetary radius. This unusual geometry results in a highly asymmetric magnetosphere," http://en.wikipedia.org/wiki/Uranus#Magnetic_field. In other words the planet itself is much more tilted than your average planet, and due to this asymmetric geometry it also has an asymmetric magnetosphere. At the very least it makes sense, since the two correlate.
The water mass of Uranus alone is roughly 9.3-13.5 Earth-masses and the overall mass is around 14.5 Earth masses, where the remaining mass consists mostly of some rocky materials and other gases like helium and hydrogen. Of note, though, is that for a planet that is 14.5x more massive than Earth it is only around 99,787.21 miles in circumference around the equator (160,591.9 km), making it only about 4x the "size" of Earth even though it's mass might lead you to think it's far larger. This is probably because it is basically a frozen planet, where even its center is considered somewhat cool. For new readers of astronomy, when it comes to mass and size, just think of how many Earth's can fit inside the planet when astronomers say "masses," yet this is not the same thing as size, since Uranus is clearly many times more massive than Earth, yet it's overall size could not fit 14.5 Earth's inside of it- only 4, actually. This is because an object's mass in outer space also correlates to its density, causing something very large to be mushed even smaller, making size deceiving. This is what makes astronomy so much fun, because quirks like these really pull people out of what I call "Earth thinking," for what goes up does not always come down in astronomy. No-thing cannot be explained, however for in astronomy a person can always count on finding an adequate, sensible but often abstract answer, since Earth is very unique in the cosmos. For more on gravity or black holes, read my article on Black holes and Gravity.
What a pretty blue planet! But looks are deceiving, since nature is beautiful and deadly at the same time, as is Uranus. The surface temperature is cold enough to turn the air you exhale immediately into frozen vapors and any air you inhale to ice your lungs would instantly frostbite your alveoli. Yes, that is quite cold, but that's ignoring the fact that a person could never even inhale on the planet itself since the gravity would mush them into an icy puddle of guts instantly. Very cold indeed. Uranus is very interesting none-the-less, though, because it is almost entirely made of water that's deep-frozen, although it's not exactly the water you would find on Earth. It's tenuous atmosphere (if it could be called that) is so thin it can hardly be considered an atmosphere, yet a layer of gas is there, consisting primarily of helium, hydrogen, and methane, reaching temperatures of -371.47°F (49 K), the coldest recorded temperature of any planet in the solar system, even Neptune. There are virtually no clouds or any discernible atmospheric features that might indicate any such atmosphere, which may be due to its low thermal flux of the core, which prevents any sort of atmospheric weather conditions such as evaporation of water, rain, and clouds. However, even though the sunlight is barely even felt on the planet, winds on Uranus fluctuate between 90-360 mph, with highest recorded winds of 560 mph (900 kph). The fastest spinning tornado ever recorded on Earth reached 318 mph and was strong enough to shred anything in its path, and where the wind that ravaged the southern part of the United Kingdom in October 1987 was estimated to be less than 100 mph (160 km/h).
Keep up with Nasa.gov because there's so much more to learn!

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